Pigment and isoprostanoid responses to cold atmospheric plasma-induced oxidative conditions in a natural epipelic diatom assemblage

Intertidal mudflats hosting diatom-dominated microphytobenthic communities experience strong variability in environmental conditions, which can lead to cellular oxidative stress. These constraints can, in some cases, affect diatom metabolism and photosynthetic performance in the short term, potentially compromising their survival and even leading to cell death. This study investigates pigment, isoprostanoid, and photophysiological changes in a diatom assemblage originating from a natural microphytobenthic biofilm under different durations of helium-oxygen bubbling cold atmospheric plasma experimental treatments, mimicking complex oxidative conditions of the environment. To this end, 2-min and 5-min treatments were applied to the diatom assemblage, and metabolic parameters were monitored over time up to +180 min after plasma treatment cessation. Despite physicochemical changes and slight perturbations in metabolite profiles induced by plasma treatments, photosynthetic capacities of the diatoms remained largely preserved. The duration-dependent effects of plasma treatments induced selective and mostly reversible changes, primarily characterized by an increase in the relative proportions of pheopigments and a decrease in the relative proportions of {beta}-carotenes following the 5-min treatment. A transient decrease in the relative proportions of the isoprostanoids 10-F4t-neuroP and 5-F2t-IsoP was also observed. By exposing natural diatom assemblage to plasma-generated oxidative conditions, this study provides novel insights into how marine microbiome respond to oxidative perturbations, contributing to our understanding of diatom success in fluctuating intertidal environments.